1. Field of the Invention
The present invention relates to an upper body opening/closing mechanism for an electronic equipment such as a copying machine or a laser printer having an upper body adapted to be opened for such purposes as maintenance and inspection.
2. Description of Related Art
In known pieces of electronic equipment such as copying machines or laser printers, the upper body of the equipment is rotatable to expose an upper surface of a lower body of the equipment for purposes such as the elimination of a paper jam, i.e., a sheet of paper stopped in a paper feed path through the equipment, exchanging a toner or other maintenance. Such a conventional piece of electronic equipment has been proposed in Japanese Utility Model Publication No. 2-744, for example.
In this proposed piece of electronic equipment, the upper body is so constructed as to selectably take a first opening position where the upper surface of the lower body is exposed at a relatively small rotative angle of the upper body and a second opening position where the upper surface of the lower body is exposed almost completely. The provision of the first opening angle is for when the operator carries out the maintenance or inspection of parts disposed at a position remote from a fulcrum of rotation of the upper body, or carries out the elimination of the paper jam, the high-temperature section located in the vicinity of the fulcrum of rotation is not greatly exposed thereby ensuring the safety of the operator when carrying out the identified actions.
This conventional electronic equipment is provided with a torsion bar for biasing the upper body in the fully open direction, so as to reduce the effort required of the operator to open the upper body. A spring constant or twist of the torsion bar is so set as to rotate the upper body beyond the first opening position in the opening direction. Further, a first stopper is provided to stop the upper body at the first opening position in such a manner that when the upper body is rotated up to the first opening position, a part of the upper body contacts with the first stopper. By displacing the first stopper, the upper body can be rotated beyond the first opening position to reach the second opening position that is the fully open position A second stopper is provided at the second opening position to stop the upper body by contact therewith.
However, this prior art has a disadvantage in that the impact force generated upon contact of the upper body with the first stopper damages the equipment.
Further, at the second opening position, an impact force is similarly generated upon contact of the upper body with the second stopper. Additionally, when the upper body is rotated to the second opening position at one stroke, the operator must remove the first stopper, which makes the action troublesome. Thus, the convenience of directly rotating the upper body to the second opening position is reduced.